1. Field of the Invention
The present invention relates to a portable radiation imaging system and a radiation image detection device for said imaging system.
2. Description of the Related Art
Apparatuses for forming radiation images, constituting a radiation source and a radiation image detection device, such as X-ray imaging systems and CR systems (as disclosed in, for example, Japanese Unexamined Patent Publication No. 55(1980)-12429 and Japanese Unexamined Patent Publication No. 56(1981)-11395 by the present applicant, etc.) are widely used in the medical field.
Today, use of the aforementioned systems is not limited to the imaging rooms of hospitals (treatment settings). Said systems are being brought into the ICU ward to take a plurality of images in a short time span, or brought out to patients and other people desiring treatment outside the hospital and imaging performed at these settings. Systems that can be carried and transported in this manner will be referred to hereinafter as portable radiation imaging systems (as disclosed in Japanese Unexamined Patent Publication No. 3(1991)-295540.
Meanwhile, to obtain a radiation image appropriate for use in diagnosis, it is necessary to maintain the relative angle between a cassette or the like which houses an image recording medium such as X-ray film or an imaging plate and the radiation source (tubular bulb) substantially perpendicular. More specifically, it is said that it is necessary to maintain the angle between the radiation emitted from the radiation source and the detection surface of the image detection device such as the aforementioned cassette or the like substantially perpendicular. This is in order to prevent the occurrence of false images in the case that, for example, a scattered ray removal grid board is utilized, and also for reasons of image reproducibility.
However, in the case that a portable radiation imaging system is utilized in, for example, an ICU ward to take many images within a short period of time, it is not possible to maintain the angle between the cassette and the radiation source perpendicular. As the angle changes for each image, diagnosis utilizing the obtained images becomes difficult. The same problem arises in the case that the system is brought outside the hospital to perform imaging in an alternate setting.